The invention relates to a device and to a method for determining the angle of rotation of a camshaft in relation to the crankshaft of an internal combustion engine.
A camshaft regulator is used to maintain an exact desired angular position course of the adjustment angle of the camshaft. Due to disturbances, such as fluctuations of the driving torque of the camshaft, deviations between the desired angle course and the actual angle course arise in practical motor operation. Reducing these deviations can lead to reduced pollutant emissions and fuel consumption, increased engine output and torque, and also reduced onboard power supply loading during engine startup and reduce engine rpm's at low idle. Especially important is the maintenance of the optimum adjustment angle during engine startup in order to reduce the high pollutant emissions in this operating state.
In DE 43 17 527 A1, a method for determining the angle of rotation Δφ of a camshaft in relation to the crankshaft of an internal combustion engine is disclosed, which features a hydraulic camshaft regulator with an electronic regulator and means for determining the angular position of the camshaft in relation to the crankshaft.
In this system, for regulating the angle of rotation Δφ of the camshaft, the rpm and the angular position of the crankshaft and camshaft are detected. Trigger wheels, which are mounted on the crankshaft and camshaft, are used for this purpose. Each sensor detects the corresponding reference and trigger marks, which are used in the electronic regulator for determining the rpm and angular position of the shafts and for calculating the angle of rotation Δφ.
Disadvantages in this solution are the necessary expense and the insufficient accuracy of the signal detection, as well as the relatively slow and imprecise setting of the angle of rotation Δφ, which is possible only in the normal engine operation, for hydraulic camshaft regulators.